Y must be a simple character scalar or vector which is taken to be the name of an APL object or a system variable. The result returned is a nested vector of 4 elements as described below. ⎕STATE supplies information about shadowed or localised objects that is otherwise unobtainable.
| 1⊃R | Boolean vector, element set to 1 if and only if this level shadows Y. Note: (⍴1⊃R)=⍴⎕LC |
| 2⊃R | Numeric vector giving the stack state of this name as it entered this level. Note: (⍴2⊃R)=⍴⎕LC 0=not on stack 1=suspended 2=pendent (may also be suspended) 3=active (may also be pendent or suspended) |
| 3⊃R | Numeric vector giving the name classification of Y as it entered this level. Note: (⍴3⊃R)=+/1⊃R |
| 4⊃R | Vector giving the contents of Y before it was shadowed at this level. Note: (⍴4⊃R)=+/0≠3⊃R |
⎕FMT∘⎕OR¨'FN1' 'FN2' 'FN3'
∇ FN1;A;B;C ∇ FN2;A;C ∇ FN3;A
[1] A←1 [1] A←'HELLO' [1] A←100
[2] B←2 [2] B←'EVERYONE' [2] ∘
[3] C←3 [3] C←'HOW ARE YOU?' ∇
[4] FN2 [4] FN3
∇ ∇
)SI
#.FN3[2]*
#.FN2[4]
#.FN1[4]
⎕STATE 'A'
1 1 1 0 0 0 2 2 0 HELLO 1
⎕FMT∘⎕OR¨'foo' 'goo'
∇ foo;⎕IO ∇ goo;⎕IO
[1] ⎕IO←0 [1] ⎕IO←1
[2] goo [2] ⎕STATE'⎕IO'
∇ ∇
foo
1 1 0 0 ¯1 ¯1 0 1